Without limiting the scope of the disclosed invention, the background is described in connection with a novel hook device used for lifting tubes and pipes.
The invention primarily falls within Group Art Unit 3652, Patent Class 294 (Handling: Hand and Hoist-Line Implements) and Sub Classes 82.11 (Hoist-Line or Grab Hook: Cable and Hook Tackle), 82.17 (Hoist-Line Or Grab Hook: Locking Device (i.e. Hook Throat Closure), and 82.24 (Hoist-Line or Grab Hook: Load Releasing Means), but is not limited to the aforementioned primary group art unit number, or the patent class, or the sub classes. The safety latching mechanism can be applied to: oilfield related tubing pipe hooks (as highlighted in this application), overhead hoist hooks, winch line hooks, chain hooks, tie down strap hooks, support hooks, and many more attachment devices.
The invention's design and development is a direct result of a customer requesting an improved tubing/pipe lifting device for use on their well service rig. Tubing lifting hooks in the past were often made from a metal rod bent in a ‘J’ shape with a connector on the top of the T to attach to a wire line which raised and lowered the pipe hook and the pipe. The pipe hook which we used for reference in our design was cut out of 1¼ inch steel plate shaped as an elongated T with a hole at the top of the ‘J’ for the wire line to attach to. A sheet metal cap which slipped over the opening of the bottom of the T helped to retain the pipe in the hook. The metal cap which was formed around the upper section or handle was manually moved up to allow the pipe to be removed and lowered to retain the pipe. The metal cap had to be manually held up to keep it from falling and covering the hook opening when loading and unloading the pipe. Our design focused on providing a safe and easy to operate tool for picking up and laying down pipe. We extended the throat of the pipe hook which made it appear more like an inverted question mark  than a ‘J’, which also kept the center of gravity aligned with the handle of the pipe hook and the attachment hole (eye). Then we added a peninsula above the hook opening to protect the operator's hand which resulted in further encasing the pipe resting area. We added a latch to retain the pipe within the hook area and then developed the trigger to retract the latch which allows the pipe to be removed from the hook area. The spring activated trigger and latch mechanism allows the pipe to be quickly hooked without having to press the trigger and then to safely unhook the pipe by pressing the trigger which retracts the latch. Finally a trigger guard was added to the design to protect the operator's hand and to protect the trigger from being hit accidentally which could release the pipe from the hook. Thus the present invention proposes a novel lifting hook device which is utilized in the lifting of tubes and pipes.